Skip To Content

EMF compliance and enforcement

Ensure EMF compliance for marine communications and electronics with Ofcom's simplified guidance.

On 9th Feb 2026, Ofcom published updated guidance on electromagnetic field (EMF) compliance and enforcement, this updated guidance links to the newest version of the Ofcom license condition: what you need to know as a ships radio licensee 2.2 which was published in 2022. 

All transmitting radio equipment emits EMF, boat owners must protect members of “the public” from harmful EMF emissions from all marine communications and associated electronics such as radio, radar and other equipment on a vessel and in shore-based installations such as yacht clubs. 

Ofcom includes family and friends as members of “the public” (see Section 4 of the Guidance on EMF compliance and enforcement document ). The owner, skipper, and any paid crew of the vessel are excluded but, if you are carrying family and friends on board even as crew you will need to comply. 

Workers, including crew are also protected from EMF exposure under existing health and safety legislation, The Merchant Shipping and Fishing Vessels (Health and Safety at Work) (Electromagnetic Fields) Regulations 2016 and MGN 559 (M+F) Amendment 2 Electromagnetic fields regulations 2016. 

Ofcom has also published an updated and simplified version of its EMF calculator at a new address. 

RYA guidance on compliance 

License holders are required to provide evidence that their equipment does not exceed the EMF limits. However, if any of the following apply, no further action is required: 

  • You do not transmit at power levels higher 6.1 Watts Effective Radiated Power (ERP). This means that you do not need to take any further action for any of the following: 

  • EPIRB and PLB 

  • AIS Class B transceivers 

  • MOB devices 

  • Handheld VHF Radio with or without DSC 

  • Radar Target Enhancers 

  • AIS SART and SART (Search And Rescue Transponder) 

  • Handheld satellite phone 

  • Your licence does not permit you to transmit at power levels higher than 6.1 Watts ERP. 

Otherwise, you should carry out a compliance check to ensure the antenna is far enough away from the general public when you are transmitting. You can do this by: 

  • Installing the equipment in accordance with the manufacturer’s instructions on EMF compliance. Keep a copy of the equipment manufacturer’s instructions on board the vessel. If they have been lost, they may be available and can be printed from the internet. If the equipment has been installed by a radiocommunications industry professional, ask the installer to provide appropriate EMF compliance records to be kept on board. 

  • If the manufacturer’s instructions cannot be located, use the EMF calculator. The calculator will calculate the safe separation distance from the antenna. You should keep a copy of this calculation onboard. 

Using the EMF calculator  

The calculator is very basic, however, whilst it is simple to use, it does use some technical terminology that goes way beyond the knowledge of the average marine radio operator. 

  •  ERP (Effective Radiated Power): ERP is the transmitting power of your equipment at the antenna. The Maximum ERP for a handheld VHF radio is 5w and 25W for a fixed VHF radio. For Radar this is in the order of 20W. 
  •  EIRP (Effective Isotropic Radiated Power): EIRP is calculated by multiplying the equipment’s ERP by a factor of 1.64. The EMF calculator lets you choose ERP or EIRP as an input parameter. 
  • Operating frequency: frequency in MHz that the equipment is transmitting, for example a VHF marine band radio transmits on 156MHz, X band radar operates between 8000MHz - 12000MHz 
  • Maximum transmission time: this is used to calculate the average radiated power in a six-minute period. For example, if you usually transmit short messages of up to ten seconds but do this is up to e.g. six times in a busy six-minute period, you should use a maximum transmission time of 1 minute (6 x 10 seconds) 

When you input ERP/EIRP, maximum transmission time and operating frequency, the calculator will determine the separation distance to be maintained between the antenna and the public. 

User manuals should provide details of transmitting power and operating frequency. You decide the maximum transmission time. If you still cannot find out what the ERP is you can use the power calculation tab in the EMF Calculator. 

Here are some examples: 

VHF  

  • A VHF radio transmitting on 156MHz at 25watts ERP for 100% of the time would require a separation distance of 2.04m. 
  • If you know that the radio will not transmit continuously, you can take this into account in the calculator. For example, if you know that the radio will not be used for more than 50 % of the time in a 6 minute period, you can enter this into the calculator instead which gives a separation distance of 1.45m. In reality, you will probably be transmitting far less than this. 
  • As most VHF transmissions are transmitted at 1 Watt, the safe separation distance from the antenna is easily achieved, however, it is recommended that you keep a note of the safe separation distance for transmissions at 25 watts. 

Radar  

  • Similar calculations should be conducted for radar. Most marine installations will be operating on X band in the 9GHx to 12GHz range, 1GHz = 1000MHz 
  • A marine radar transmitting all the time on 9000MHz at 20 watts ERP would require a separation distance of 0.82m. 

As can be seen from the examples above, compliance is easily achievable. 

Time period for compliance 

The 9 February 2026 update to Ofcom’s Guidance on EMF Compliance and Enforcement represents a shift from "educational guidance" toward a "strict enforcement" model.

Fixed Penalty Notices (FPNs)

Ofcom has the power to issue fixed penalty notices if it has reason to believe that a person has committed a breach of the 2006 Act.

Shared Site Responsibility (Marinas & Yacht Clubs)

Specific language regarding "Shared Sites," which affects yacht clubs and marinas with multiple antennas (VHF, AIS, Wi-Fi, and 5G small cells) is now included.

Ofcom have produced a shared site compliance flowchart to help spectrum users assess whether they need to take into account another user’s equipment on a shared site.

Member of the Public

Anyone else is a member of the general public for the purposes of the EMF condition. The general public can therefore include family, friends, lodgers, visitors, neighbours, passengers, paying customers and all other members of the general public of all ages.

Where any of these individuals are not (i) the licensee, owner, operator or installer of the relevant radio equipment; or (ii) a worker who should be protected from EMF exposure under existing health and safety legislation, the EMF condition requires spectrum users to ensure they are not exposed to EMF in breach of the general public EMF limits.

What stayed the same?

  • The 6.1W ERP Threshold: Handheld VHFs (usually 5W or 6W) and AIS Class B units remain exempt from needing an assessment.
  • The Emergency Exemption: You are still legally allowed to exceed EMF limits if you are transmitting a distress (Mayday) or urgency (Pan-Pan) call.
Accessibility